/* 顶部标签 */
.topbar{
    /* 固定定位 */
    position: fixed;
    top: 0;
    left: 0;
    height: 54px;
    width: 100%;
    opacity: 0;
    background-color: rgba(25,196,138,.9);
    transition: opacity .5s;
    z-index: 99;
}
.topbar-active{
    opacity: 1;
}